This invention relates generally to television signal switching and particularly to an automatic switch that selectively supplies television signals to a television signal utilization device, such as a VCR or television receiver from a decoder output and a cable input in response to operation of the decoder.
In conventional CATV systems, a television receiver is typically connected to an RF output terminal of a decoder. The decoder, which also includes an RF input terminal connected for receiving a plurality of program channel signals from the CATV distribution system, only produces a signal output on one channel, generally VHF channel 3 or VHF channel 4. This arrangement restricts the use of the television receiver to channel 3/4 and requires that various program channel selections be made via the tuner in the decoder. The panoply of functions available on a modern television receiver are therefore not available to the viewer. This is unfortunate because in most CATV systems, the majority of the program channel signals are not encoded and may be received and processed directly by a television receiver that has a tuner capable of receiving the program channel frequencies. Here again, most modern television receivers are capable of directly receiving all CATV channel signals.
Viewers will sometimes use a signal splitter along with a manually operable A/B switch to allow selective coupling of the decoder output and input CATV signal to the input of the television receiver. This, however, requires manual operation of the A/B switch between the decoder output and the CATV input.
With the automatic switch of the invention, such manual operations are avoided because the input television signals automatically bypass the decoder when the decoder is not needed, i.e., when it is turned off. The automatic switch is in a separate enclosure that is connectable to the decoder and television receiver, or other television signal utilization device by means of coaxial cables. A built-in power supply for operating the automatic switch is controlled by a line cord connection to a switched outlet on the decoder.